Alpha-lipoic acid is 1,2-dithia-cyclopentane-3-valeric acid.
Alpha-lipoic acid is distributed widely in plants and animals in the form of the R-enantiomer; it acts as a coenzyme in many enzymatic reactions, constitutes a growth factor for certain bacteria and protozoa and is used to treat death-head mushroom poisoning. The alpha-lipoic acid racemate also has anti-inflammatory, antinociceptive (analgesic) and cytoprotective, neuroprotective, anti-allergic and antitumor properties.
The separated optical isomers of alpha-lipoic acid (R- and S-form, i.e. R-alpha-lipoic acid and S-alpha-lipoic acid), have different properties from each other and from the racemate. The R-enantionmer has a predominantly anti-inflammatory effect, and the S-enantiomer has a predominantly antinociceptive effect. The anti-inflammatory effect of the R-enantiomer is, for example, 10 times stronger than that of the racemate. The antinociceptive (analgesic) effect of the S-enantiomer is for example up to 6 times stronger than that of the racemate.
The enantiomers thus constitute very much more specific and stronger acting active substances as compared to the racemate.
These effects are described in Published European Patent Application EP-A 901213405.
Vitamin A is essential for growth, for bone development, normal function of the reproductive organs and the eyes and, above all, for the structure and function of mucous membrane epithelium.
Vitamin E essentially maintains the function of all cells, also those of the nervous system. Its main function is to protect lipids from peroxidation. Japanese published patent 3-193778 describes esters of lipoic acid with tocopherols. These tocopherol esters of lipoic acid are used to treat UV-erythemas.
Vitamin B1 is mainly active in thiamine deficiency syndrome, i.e. with severely deficient diet, long-term parenteral feeding, zero-diet, hemodialysis, malabsorption and alcohol abuse.
Vitamin B2 mainly acts in deficiency symptoms caused by alcohol abuse or insufficient intake of milk and milk products.
Vitamin B6 mainly acts in deficiency symptoms caused by alcohol abuse or chronic medication intake (oral contraceptives, isoniazid).
Vitamin B12 mainly acts in strict vegetarians, after gastric resection and atrophy of the mucous membrane or intestinal disorders which lead to deficiency symptoms such as anaemias, precipitations of the peripheral and central nervous system and polyneuropathies.
Vitamin C is part of the biochemical redox system and is involved in numerous electron transport reactions. These include, inter alia, collagen synthesis, noradrenaline, dopamine and serotinin synthesis and the degradation of 4-hydroxyphenyl- pyruvate. It also encourages the absorption of iron and has a stimulating effect on leucocyte phagocytosis activity. Together with carotinoids, vitamin A and E, vitamin C has been shown to have an antitumor effect.